Aberrant expression of cell cycle regulatory proteins characterizes many human tumors, including lung cancer. Dysregulated expression of cyclin B1 (CB1), demonstrated by constitutive overexpression and mislocalization in the cytoplasm rather than the nucleus, is especially significant because it contributes to malignant transformation and increased metastatic potential of tumor cells. Aberrant expression of CB1 is a result of functional inactivation of the tumor suppressor gene p53, an early event in the progression from premalignant to malignant lesions in the lung, suggesting that it could be a marker and a potential target in early as well as late stage cancer. CB1 overexprression in lung cancer elicits specific antibodies and T cells. CB1-specific antibodies are also seen in heavy smokers who are at high risk for developing lung cancer. Experiments, in mice show that anti-CB1 specific immune responses can protect from tumor challenge. The first hypothesis to be tested in Project 2 is that vaccines will elicit or boost CB1-specific immunity in lung cancer patients and that will result in an anti-tumor effect. Our second hypothesis is that the immune response against CB1 could be a biomarker of risk for development of future lung cancer in subjects with a positive smoking history or for recurrence among early-stage patients newly diagnosed with lung cancer. These two hypotheses are being tested in three specific aims. In Specific Aim 1 we propose to carry out clinical trials testing CB1 vaccines safety and immunogenicity in stage I and II lung cancer patients undergoing tumor resection. In Specific Aim 2 we will analyze and compare the quantitative and qualitative features of anti-cyclin B1 immunity in cancer patients and high-risk individuals in an attempt to elucidate important immune correlates of protection. In Specific Aim 3 we propose to evaluate the diagnostic and prognostic value of anti-CB1 antibodies in high risk individuals and cancer patients and to compare it to other diagnostic and prognostic markers studied in the SPORE projects. The overall goal is to translate the new knowledge acquired in the past grant period on the mechanisms of CB1 dysregulation and anti-CB1 immunity, to diagnosis, prognosis and therapy of lung cancer.